Eur. Phys. J. A 14, 169-178 (2002)
DOI: 10.1140/epja/i2002-10004-2
Langevin description of charge fluctuations in fission of highly excited nuclei
A.V. Karpov and G.D. AdeevDepartment of Theoretical Physics, Omsk State University, Mira prospect 55-A, Omsk, 644077 Russia karpov@phys.omsu.omskreg.ru
adeev@univer.omsk.su
(Received: 22 October 2001 / Revised version: 25 March 2002 Communicated by J. Äystö)
Abstract
A stochastic approach to fission dynamics based on three-dimensional
Langevin equations is used to study charge fluctuations in
fission of highly excited nuclei. Elongation, neck and
charge asymmetry parameters are chosen as relevant collective
coordinates. Using as an example
induced fission of
in a broad range
of excitation energies (from
60 to
),
the isobaric charge variance is investigated to obtain information
on nuclear dissipation. The friction parameter of the charge mode is
calculated under the assumption of both the one-body and two-body
mechanisms of nuclear viscosity. The results obtained for the variances of
the charge distribution within the applied approach reveal that the optimal
reproduction of the available data is achieved with the value of the
two-body viscosity coefficient
that is close to those deduced earlier from the description
of the fission fragment mass-energy distribution. The expression for the
friction parameter of the charge mode is derived within
the one-body mechanism of nuclear dissipation.
The one-body mechanism of nuclear dissipation also
provides a good reproduction of data on the isobaric
charge variance without any adjustable strength parameter.
25.85.-w - Fission reactions.
05.10.Gg - Stochastic analysis methods (Fokker-Planck, Langevin, etc.).
02.50.Ey - Stochastic processes.
© Società Italiana di Fisica, Springer-Verlag 2002
